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-   -   Aero: Why do the guys with flat undertrays not run their splitters higher? (https://www.miataturbo.net/race-prep-75/aero-why-do-guys-flat-undertrays-not-run-their-splitters-higher-64212/)

owenwilliams 03-14-2012 04:36 PM

@bellwilliam: "Why do the guys >with flat undertrays< not run..." ;)
Also I explained my appreciation of the regs in F1, and why the high nose started as a genuine aero idea and has since become mandatory for different, safety-related reasons. Note that the bent nose thing this year has come about as a result of regs actually limiting the height of the nose, again for safety reasons. So it can't be too high, or too low, but juuuuuust right.

I posted this vid in the Random Picture thread a while ago, but since there might be people interested in race car aero reading this that haven't seen it, I'll post it again. I just hope you overseas guys have access to BBC website media. It's worth a watch if you're a geek. Which we all are. http://www.bbc.co.uk/sport/0/formula1/16864721

greeenteeee 03-14-2012 07:37 PM


Originally Posted by bellwilliam (Post 848260)
always thought:

1. if you have a flat bottom car, air going under the car is a good thing. speed up the flow, lower pressure, more downforce.
2. on a Miata, where it is an aero nightmare underneath. you wouldn't want air under the car.

also never look at F1 (or most spec race cars) for aero idea, they are most often regulated by rule.

this is essentially it. from what i've read about ride heights, ground clearances etc.

the idea is to keep air underneath low psi high velocity. if there is too much of an opening at the front, it will slow (bernoulli). slow air is closer to stagnant air. stagnant air is drag.

a production car with bad underbody aero can usually benefit from a higher ride height and may suffer from drag if it is lowered too much, whereas a car with flat underbody can benefit from being lower (again, pinch the air, low psi, high velocity, bernoulli).

the opel calibra has a Cd of 0.26 (today's prius's are 0.26, 0.25). opel made the middle section of their bumper higher than the outsides (similar to Racing Beat II bumper) to let more air under the car.. this was a big part of them reducing the Cd to 0.26. #foodforthought.

on my miata, with the drag / coast down tests i've done with it, my pinch height is 3.75/4.00 (95.25mm/101.6mm). front subframe is about 3.5" from ground. my tests show less drag with an airdam at 115mm vs my airdam at 65mm. the latter airdam also includes an undertray which reduces front lift.

my undertray is 2" higher than the lowest part of the car (approx 3.5" at front subframe) but my front airdam is 65mm (2.5") from the ground.

ZX-Tex 03-15-2012 07:32 AM


Originally Posted by triple88a (Post 848258)
Hyper has returned? :rofl:

No, because IIRC Hyper would never admit he was wrong even if he was obviously wrong, like claiming the sky was green with purple polka-dots.

owenwilliams 03-19-2012 03:57 PM

PS, thanks to whoever gave me -1 props on most of my posts here. To be fair, it was kinda deserved.

miata_racer 03-19-2012 09:47 PM

I had the pleasure of banning him on CR.net recently for a week :)


Originally Posted by ZX-Tex (Post 848486)
No, because IIRC Hyper would never admit he was wrong even if he was obviously wrong, like claiming the sky was green with purple polka-dots.


buffon01 03-20-2012 12:27 AM


Originally Posted by miata_racer (Post 850487)
I had the pleasure of banning him on CR.net recently for a week :)

Only a week? :facepalm:


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